In Ruby, you check with
nil?
if an object is nil:
article = nilarticle.nil? # => true
empty?
checks if an element - like a string or an array f.e. - is empty:
# Array
[].empty? #=> true
# String
"".empty? #=> true
Rails adds the method blank?
to the Object
class:
An object is blank if it‘s false, empty, or a whitespace string. For example, "", " ", nil, [], and {} are blank.
This simplifies
if !address.nil? && !address.empty?
to
if !address.blank?
.nil?
- It is Ruby method
- It can be used on any object and is true if the object is nil.
- "Only the object nil responds true to nil?" - RailsAPI
nil.nil? = true
anthing_else.nil? = false
a = nil
a.nil? = true
“”.nil = false
.empty?
- It is Ruby method
- can be used on strings, arrays and hashes and returns true if:
Quick tip: !obj.blank? == obj.present?
activesupport/lib/active_support/core_ext/object/blank.rb, line 17 # (Ruby 1.9)
def present?
!blank?
end
以上就是【转】ruby中nil?, empty? and blank?的选择的详细内容,更多关于【转】ruby中nil?, empty? and blank?的选择的资料请关注九品源码其它相关文章!